Ebola contact tracing and ring vaccination — DTM&H MCQ

Correct answer: A — Contact tracing with monitoring and ring vaccination where available

The correct answer is A, contact tracing with monitoring and ring vaccination where available. Ebola spreads through direct contact with body fluids of symptomatic cases or corpses, so funeral and household exposures are classic high-risk transmission events requiring systematic contact listing, risk categorisation and daily symptom and temperature monitoring for the full 21 day incubation period. Where an effective, strain-matched vaccine such as rVSV-ZEBOV is available, ring vaccination of contacts and contacts of contacts around a confirmed case is added to monitoring to build a protective barrier and interrupt onward chains rapidly. This combined strategy of case finding, exposure risk stratification, exit screening at 21 days and targeted vaccination underpins UK and WHO outbreak response protocols and is what breaks transmission fastest in a funeral-linked cluster. Why the other options are wrong: D. Water chlorination as the single intervention: Ebola transmission is via direct contact with infected fluids, not the faecal-oral or waterborne route, so chlorination alone has no meaningful effect on this outbreak. C. Routine malaria chemoprophylaxis for contacts: this treats a different pathogen and does nothing to identify, monitor or protect Ebola-exposed contacts; malaria co-endemicity is a diagnostic confounder, not an Ebola control measure. B. Delay action until a second generation of cases: waiting allows further amplification through additional unsafe funerals and household exposures, the opposite of the immediate case and contact management that outbreak control demands. E. Mass albendazole for the district: albendazole treats helminths and has no antiviral or outbreak control role in a viral haemorrhagic fever response. Key point: In Ebola outbreaks, rapid contact tracing with structured 21 day monitoring plus ring vaccination (when a matched vaccine is available) is the single most effective measure to halt funeral and household-associated transmission chains.

Reference: UK Health Security Agency (UKHSA), Viral Haemorrhagic Fever: Algorithm and Guidance on Management of Patients and Contacts; WHO Ebola Virus Disease Outbreak Response Guidance (ring vaccination with rVSV-ZEBOV), gov.uk/government/publications/viral-haemorrhagic-fever-algorithm-and-guidance-on-management-of-patients